It's *totally* a matter of opinion.
However, I have only heard the Biblical argument as "the Bible says Thou Shalt not kill."
There are ways of interpreting, though, which make it interesting whether or not you'd even say a fetus is considered a life by the Bible.
To me that makes it sound as if the soul and life begin at first breath. Again, up to many different interpretations!
ETA: Personally, I don't look at abortion as a Biblical issue, but many others seem to. Pro-lifers, anyway.